Specification:Interface has a locking mechanism, easy to install.It is light and convenient, easy to install and easy to take.Used for lengthening the shank of milling cutters, engraving or trimming machine accessories.Type: Extension RodMaterial: Carbon SteelFeatures: Durable, Practical, Turning ToolShank Diameter: 1/4", 6mm, 8mm, 12mm, 1/2"Size: 8.2cm x 2.7cm/3.23" x 1.06" (Approx.)Specification:1 : Extension rod 6mm to 6mm2 : Extension rod 1/4 inch to 1/4 inch3 : Extension rod 1/4 inch to 8mm4 : Extension rod 8mm to 12mm5 : Extension rod 8mm to 1/2 inch6 : Extension rod 8mm to 8mm7 : Extension rod 12mm to 12mm8 : Extension rod 1/2 inch to 1/2 inchNotes:Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Extension Rod (Others Not Included)